Encephalitis literally means brain infection. Strictly speaking, "-itis" means inflammation, which includes redness, swelling, pain, and warmth, and can be due to infection or other types of irritation. The brain can become infected with many different germs, including viruses, bacteria, fungi, and parasites. The symptoms of encephalitis include fever, chills, headache, altered mental status (confusion, delirium, and agitation), stiff neck, nausea, vomiting, seizures, coma (unconsciousness), and death. Viral brain infections are rarely as serious as other kinds of encephalitis.

Japanese encephalitis (JE), St. Louis encephalitis (SLE), and tick-borne encephalitis (TBE) are all caused by viruses in the flavivirus group. The viruses of these diseases are transmitted by mosquitoes or ticks. Each virus is particular to certain regions of the world. The following geographical distributions are typical for each disease: Japanese encephalitis is found in Asia and Australia; St. Louis encephalitis is found in North, Central, and South America. Tick-borne encephalitis is found in Europe and Asia.

JE can be a risk to travelers in rural areas of Japan, where there are 30,000 to 50,000 cases annually. Fewer than one case per year is reported in Americans traveling to or working in Asia. Birds and domestic pigs can carry the virus. Symptoms appear six to eight days after the mosquito bite. JE kills roughly 30% of its victims. Another 30% will have serious and permanent brain damage. A vaccine known as Japanese encephalitis virus vaccine is available, but it is expensive and occasionally causes significant side effects. Ten percent of patients report fever, headache, malaise, rash, and other reactions such as chills, dizziness, muscle pain, nausea, vomiting, and abdominal pain. Twenty percent report pain at the injection site. A few suffer generalized allergic reactions.

SLE is similar to West Nile virus, LaCrosse virus, and eastern and western equine encephalitis. Birds can carry the virus. Symptoms appear five to 15 days after the mosquito bite. It kills 5% to 30% of its victims. Between 1964 and 2005, 4651 cases were reported in the United States. It occurs most often in warmer weather, when mosquitoes abound.

TBE occurs in many parts of Europe and Asia. Several thousand cases are reported every year. The disease can also be acquired from raw cow, goat, and sheep milk, and from the air in infectious disease laboratories. Symptoms appear seven to 14 days after the tick bite. Permanent brain damage occurs in 10% to 20% of patients. Death occurs in only one percent to two percent of victims.

Symptoms of Japanese encephalitis (JE) appear six to eight days after the mosquito bite. JE kills roughly 30% of its victims. Another 30% will have serious and permanent brain damage.

Symptoms of St. Louis encephalitis (SLE) appear five to 15 days after the mosquito bite. It kills 5% to 30% of its victims.

Symptoms of tick-borne encephalitis (TBE) appear seven to 14 days after the tick bite. Permanent brain damage occurs in 10% to 20% of patients. Death occurs in only one percent to two percent of victims.

The most definitive method of diagnosis of viral encephalitis is a brain biopsy, in which a small sample of brain tissue is removed and analyzed in a laboratory.

The typical methods for identifying viruses that may cause encephalitis are products of molecular biology research. Virus detection can be accomplished by fluorescent tagging using antigen-antibody reactions or by polymerase chain reaction (PCR). Their presence can also be detected by isolation of antiviral antibodies in the blood or spinal fluid of patients.

Fluorescent tagging is done by creating an antibody to the virus, attaching to it a chemical moiety that glows under ultraviolet light, mixing the tag with the sample to be tested, and looking for the fluorescent signature in the mixture.

PCR is a method of multiplying a segment of a gene millions of times so that it can be identified by fluorescence or other similar techniques. Antibodies in infected individuals take time to develop as the disease progresses, but they can also be identified by standard medical laboratory techniques.

Specific treatments for Japanese encephalitis, St. Louis encephalitis, or tick-borne encephalitis are currently unknown. Treatment generally focuses on the reduction of symptoms and prevention or management of complications. Therefore, treatment usually does not kill the virus but is directed towards sustaining the patient until the disease runs its course.

Treatment of viral encephalitis should focus on maintaining normal breathing, kidney and bladder function, fluid and electrolyte balance, and proper nutrition. In addition, patients should be monitored for additional infections, fevers, and bedsores.

Increased pressure in the brain should be monitored. Diuretics, mannitol, and hyperventilation may reduce this pressure. If seizures result from viral encephalitis, anti-seizure drugs such as phenytoin, valproic acid, and carbamazepine may be used.

For tick-borne encephalitis, specific immunoglobulin is available. An immunoglobulin is an antibody that is prepared in an animal and then purified and injected into a patient. Snake venom antitoxin is an example. These antibodies perform the same function as antibodies produced by the patient, but there is no wait time for the patient to produce them, which may take so long that the disease does its damage before they become effective.

Note: There is a currently a lack of scientific data on the use of integrative therapies for the treatment or prevention of viral encephalitis. The therapies listed below have been studied for viral infections in general, should be used only under the supervision of a qualified healthcare provider, and should not be used in replacement of other proven therapies.

Unclear or conflicting scientific evidence:

Alizarin: Limited available evidence suggests that alizarin may improve various herpes infections. Additional study is needed before a firm recommendation can be made. Avoid if allergic or hypersensitive to alizarin or any plants in the Rubiaceae family. Alizarin may be toxic and should not be handled for long periods of time, rubbed in the eyes, or eaten. Avoid if pregnant or breastfeeding.

Astragalus: Astragalus products are derived from the roots of Astragalus membranaceus or related species, which are native to China. In traditional Chinese medicine, astragalus is commonly found in mixtures with other herbs, and is used in the treatment of numerous ailments, including heart, liver, and kidney diseases, as well as cancer, viral infections, and immune system disorders. Anti-viral activity has been reported with the use of astragalus in laboratory and animal studies. Limited human research has examined the use of astragalus for viral infections in the lung, heart (pericarditis, myocarditis, endocarditis), liver (hepatitis B and C), cervix (papilloma virus), and in HIV disease. Studies have included combinations of astragalus with the drug interferon, or as a part of herbal mixtures. However, most studies have been small and poorly designed. Due to a lack of well-designed research, firm conclusions cannot be drawn.

Avoid if allergic to astragalus, peas, or any related plants, or with a history of Quillaja bark-induced asthma. Avoid with aspirin or aspirin products or herbs or supplements with similar effects. Avoid with inflammation (swelling) or fever, stroke, transplant or autoimmune diseases (like HIV/AIDS). Stop use two weeks before surgery/dental/diagnostic procedures with a risk of bleeding and avoid use immediately after these procedures. Use cautiously with bleeding disorders, diabetes, high blood pressure, lipid disorders or kidney disorders. Use cautiously with blood-thinners, blood sugar drugs, or diuretics or herbs and supplements with similar effects. Avoid if pregnant or breastfeeding.

Blessed thistle: Blessed thistle leaves, stems, and flowers have traditionally been used in "bitter" tonic drinks and in other preparations taken by mouth to enhance appetite and digestion. Evidence of activity of blessed thistle against herpes viruses, influenza, or poliovirus is currently lacking in available preliminary research. Effects of blessed thistle (or chemicals in blessed thistle called lignans) against HIV are not clear. Human research of blessed thistle as a treatment for viral infections is lacking.

Avoid if allergic to blessed thistle, mugwort, bitter weed, blanket flower, chrysanthemum, coltsfoot, daisy, dandelion, dwarf sunflower, goldenrod, marigold, prairie sage, ragweed, Echinacea or any plants of the Asteraceae or Compositae families. Use cautiously with peptic ulcer disease. Avoid with a history of bleeding diseases or gastroesophageal reflux disease (GERD), or if taking drugs for blood thinning, stroke, stomach diseases, or to control stomach acid. Avoid if pregnant or breastfeeding. Stop use two weeks before surgery/dental/diagnostic procedures with bleeding risk and do not use immediately after these procedures.

Cranberry: Cranberry is popular as a food, and is often consumed as relish, sauce, jam, juice, or dried berries. Limited laboratory research has examined the antiviral activity of cranberry. Reliable human studies supporting the use of cranberry in this area are currently lacking. Avoid if allergic to cranberries, blueberries, or other plants of the Vaccinium genus. Sweetened cranberry juice can affect blood sugar levels. Use cautiously with history of kidney stones. Avoid more than the amount usually found in foods if pregnant or breastfeeding.

Focusing: Early research showed that increased experiential involvement (an indication of focusing taking place) did not have an effect on antibody titers to Epstein-Barr virus. More studies in the area of immune function and antibody production are required before a recommendation can be made in this area.

Green tea: Preliminary research suggests that green tea decreases viral load in carriers of the HTLV-1 virus. Additional well-designed controlled research is needed before a recommendation can be made for or against use of green tea in the treatment of HTLV-1 carriers. Avoid if allergic or hypersensitive to caffeine or tannin. Use cautiously with diabetes or liver disease.

Sorrel: Historically, sorrel has been used as a salad green, spring tonic, diarrhea remedy, weak diuretic, and soothing agent for irritated nasal passages. Sorrel has been used with other herbs to treat bronchitis and sinus conditions in Germany since the 1930s. There is currently a lack of well-conducted published studies that demonstrate antiviral or antibacterial activity of sorrel. In available laboratory study, sorrel did not demonstrate activity against herpes simplex virus-1, herpes simplex virus-2, HIV, B. subtilis, E. coli, Proteus morganii, Pseudomonas aeruginosa, P. vulgaris, Serratia marcescens, or Staphylococcus aureus.

Avoid with a known allergy to sorrel. Avoid large doses of sorrel because there have been reports of toxicity and death, possibly due to oxalates found in sorrel. Tinctures contain high levels of alcohol and should be avoided when driving or operating heavy machinery. High alcohol sorrel formulations may also cause nausea or vomiting when taken with the prescription drugs metronidazole (Flagyl®) or disulfiram (Antabuse®). Avoid if pregnant or breastfeeding.

Turmeric: The rhizome (root) of turmeric (Curcuma longa Linn.) has long been used in traditional Asian medicine to treat gastrointestinal upset, arthritic pain, and "low energy." Evidence suggests that turmeric may help treat viral infections. However, there is currently not enough human evidence in this area. Well-designed trials are needed to determine if these claims are true.

Avoid if allergic or hypersensitive to turmeric, curcumin, yellow food colorings, or plants belonging to the Zingiberaceae (ginger) family. Use cautiously with a history of bleeding disorders, immune system deficiencies, liver disease, diabetes, hypoglycemia, or gallstones. Use cautiously with blood-thinners, such as warfarin (like Coumadin®), and blood sugar-altering medications. Avoid in medicinal amounts if pregnant or breastfeeding. Turmeric should be stopped prior to scheduled surgery.

Vitamin A: The role of vitamin A in the prevention, transmission, or treatment of HIV is controversial and not well established. A clear conclusion cannot be formed based on the available scientific research. Vitamin A supplementation has also been suggested to help prevent NoV infection in children and reduce the symptoms associated with NoV infections. Additional research is needed in this area.

Except in rare circumstances, ordinary precautions against insect bites are advised to prevent these diseases. Insect repellants, clothing that covers most of the body, and socks and bed nets soaked in insecticide (permethrin) will prevent most arthropod-borne diseases.

A vaccine for Japanese encephalitis is available, but it is expensive and occasionally causes significant side effects. Ten percent of patients report fever, headache, malaise, rash, and other reactions such as chills, dizziness, muscle pain, nausea, vomiting, and abdominal pain. Twenty percent report pain at the injection site. A few suffer generalized allergic reactions. This vaccine is recommended only for those anticipating extended stays in high-risk regions.

A vaccine for tick-borne encephalitis is available in some countries but not in the United States. Its side effects include high fevers, particularly in children.

Individuals who travel to regions where these diseases are found must inform themselves of the risks and take whatever precautions are advised. In most cases, standard traveler vaccinations and routine precautions against known sources of disease are adequate.

Viral encephalitis is a brain infection caused by one of several viruses. Japanese encephalitis (JE), St. Louis encephalitis (SLE), and tick-borne encephalitis (TBE) are all caused by viruses in the flavivirus group. The viruses of these diseases are transmitted by mosquitoes or ticks.

Japanese encephalitis (JE) can be a risk to travelers in rural areas of Japan, where there are 30,000 to 50,000 cases annually. Fewer than one case per year is reported in Americans traveling to or working in Asia. Birds and domestic pigs can carry the virus.

St. Louis encephalitis (SLE) is similar to West Nile virus, LaCrosse virus, and eastern and western equine encephalitis. Birds can carry the virus. Between 1964 and 2005, 4651 cases were reported in the United States. It occurs most often in warmer weather, when mosquitoes abound.

Tick-borne encephalitis (TBE) occurs in many parts of Europe and Asia. Several thousand cases are reported every year. The disease can also be acquired from raw cow, goat, and sheep milk, and from the air in infectious disease laboratories.

Japanese encephalitis (JE), St. Louis encephalitis (SLE), and tick-borne encephalitis (TBE) are all caused by viruses in the flavivirus group. The viruses of these diseases are transmitted by mosquitoes or ticks. Each virus is particular to certain regions of the world. The following geographical distributions are typical for each disease: Japanese encephalitis is found in Asia and Australia; St. Louis encephalitis is found in North, Central, and South America; tick-borne encephalitis is found in Europe and Asia.

Vaccine development and improvement: Vaccination has been the primary means by which viral illnesses have been reduced over the past century. Vaccines traditionally have employed a killed or weakened virus that stimulates an immune reaction without causing the disease. Recently molecular biology techniques have been used to increase the safety and potency of vaccines by genetically altering the virus. For example, genes from a dengue virus were spliced into the genome of a harmless virus from the same flavivirus family. These combinations are called chimera. When this chimera was injected into a mouse, the mouse developed antibodies to the dengue virus.

Antiviral drugs: Antiviral drugs have been developed using genetic techniques. Once the gene structure of a virus in known, specific drugs can target the critical genes in the virus that cause it to be infectious. The AIDS virus, for example, has several enzymes (proteins that mediate chemical reactions) that allow it to multiply within human cells. Drugs such as reverse transcriptase inhibitors and protease inhibitors block the action of these enzymes.

Progress in virus research has made great advances in the past several decades. The ability to determine the exact structure of viral molecules is enabling scientists to develop chemicals that precisely target the viral molecules. Progress is also being made in identifying how diseases are spread, so that control of vectors (agents that spread disease like rats and mosquitoes) is becoming more effective. There is always an intricate and complex relationship between disease-causing agents and the hosts that harbor them. These relationships are mediated at the genetic and molecular level and each is very specific to the two organisms involved. Each must have a genetic structure that allows the other to coexist. The host's immune system must not attack the parasite. The parasite must be able to grow in the host's unique environment and must also be able to transfer from the host to a human or other animal where it causes disease.

Diagnostic tests: In the laboratory, many tests are being developed that can identify each virus, so that when treatments become available there will be no delay in using them. Many of these tests rely on identifying proteins or sequences of DNA (deoxyribonucleic acid) or RNA (ribonucleic acids) that are unique to a particular virus, creating a tag molecule that attaches to only that unique sequence and adding to the tag a label such as a fluorescent particle that can be seen. Often these tags are antibodies produced by laboratory animals when challenged with the virus product that has been isolated.

In addition to vaccine and drug development, increasing knowledge of the genetic determinants of viral and arthropod host behavior will inform efforts to eliminate these diseases before they attack humans. Genetic studies of humans will identify specific genetic profiles that are more likely to contract these diseases and more likely to have severe disease, such as those with HIV and other immune deficiencies.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.